1. Field of the Invention
The present invention relates to a display system mounted on a controllable movable body such as a vehicle (for example a display system for an instrument panel).
2. Description of the Related Art
As a display system mounted on an instrument panel of a car or the like, there has recently been proposed a display system which displays on a display (display section) information assisting the driving, such as navigation information, in addition to vehicle state information such as the running speed and engine revolutions.
In doing so, information (image data) regarding the image display is typically generated by a single CPU in a centralized manner and displayed on a display. That is to say, the CPU receives sets of information (data) detected or generated by sensors and a system, generates image data based on the supplied data and the data (for image generation) stored in a storage medium or the like, and displays, on a display, images based on the generated data.
For example, a publicly-known document 1 (Japanese Laid-Open Patent Application No. 2002-154393; published on May 28, 2002) discloses, as shown in FIG. 20, an instrument panel which is provided with an entertainment display 2002a for displaying a navigation image or the like and an information display 2003 for displaying an information service image and an alert image in accordance with a detected running state and running environment of the vehicle. The entertainment display 2002a and the information display 2003a are controlled by a CPU 2020. In other words, the CPU 2020 displays a current location on the entertainment display 2002a (navigation image) based on current location information supplied from a GPS sensor 2027 and map information stored in a ROM 2051. The CPU 2020 also displays on the information display 2003a the running state of the vehicle, which is detected by signals supplied from a vehicle speed sensor 2026 and a steering angle sensor 2025.
As shown in FIG. 19, an in-vehicle wide display 1010 disclosed by a publicly-known document 2 (Japanese Laid-Open Patent Application No. 9-123848; published on May 13, 1997) is, via an image processing device 1012 including VRAM and the like, connected to an information processing device 1016 including a CPU executing a predetermined computation process, a ROM storing a processing program, and an I/O interface. This information processing device 1016 receives sets of information from a navigation system 1022, a traffic information communication system 1024, a monitor system 1026, a sensor system 1028, and a diagnosis system 1030. Based on these sets of information, the information processing device 1016 judges the running state and obtains necessary information, and then displays various information items on the wide display 101 by means of the image processing device 1012.
According to the conventional art disclosed in the publicly-known document 1, the CPU 1020 generates the image data for a navigation image displayed on the entertainment display 1002a and also generates the data of a vehicle information image displayed on the information display 1003a. Similarly, according to the publicly-known document 2, the CPU in the information processing device 1016 generates the image data for a navigation image displayed on the wide display 1010 and the image data of a vehicle information image based on the sensor system 1028 or the diagnosis system 1030.
However, in those cases where various types of images (image data) displayed on an instrument panel are generated and displayed by a single CPU which performs many information processes, a serious trouble occurs, that is, important vehicle information (speed information and alert information and the like) essential for the driving cannot be displayed, when malfunction or thermal runaway of the CPU occurs on account of overload. In particular, the load on CPUs has recently increased because of the advance of display systems (e.g. improvement in display quality and increase in the types of entertainment to be dealt with), and hence the aforesaid trouble is very likely to occur. To put it differently, the advancement of display systems has limitations in the conventional art, in consideration of the safety of vehicles. Moreover, customization is not easily done because various processes such as the generation of different types of image data are centrally carried out by a single CPU.